Why information could be our route to the universe’s deepest secrets

Physics

Physicists are finally getting their heads round what information truly is – and using it to gain new insights into life, the universe and, well… everything

By Joshua Howgego

11 December 2019

Tokyo, Japan

AS THE messages ping, notifications buzz and headlines scream for your attention, it is easy to think you could do with a little less information. That’s bog-standard “semantic” information. It encapsulates a nugget of knowledge: a friend’s status, a place and time to meet, or the fact that the sky is blue.

Over the past century, though, physicists have dug deep into what information truly means, and uncovered deep links between it and the fabric of reality. We’re likely to be hearing a lot more of this type of information.

This all started with studies of the second law of thermodynamics, the uniquely powerful rule that describes the fundamental direction of processes in the universe. It says that stars always burn out, ice cream always melts, warm air always escapes out of a window left ajar. These processes are encapsulated by a rise in the quantity known as entropy, which measures how disordered something is on the atomic scale. More disorder means higher entropy.

What does this have to do with information? Well, the more ordered something is, the less information you need to fully describe it: compare describing a box of identical buttons with one filled with buttons in 20 different colours. In 1948, the US engineer Claude Shannon used this thermodynamic connection to come up with a new, more abstract definition of information, divorcing it from having to actually be about anything.

“Deep connections exist between information and reality’s fabric”

Abstract – and yet very real, as recent experiments have shown. In 2015, for example, Jonne Koski, then at Aalto University in Finland, and his colleagues built a tiny electronic “fridge” powered by information. “By using the information, a device that would normally heat up is actually cooled down,” says Koski. “It has a physical meaning, for sure.”

at the University of Oxford even thinks information could be the building block of a new, more powerful theory of nature. Unlike current theories that take things as they are now and predict what will happen next, it would tell us what is possible regardless of any specifics. “There are hints it could be as good if not maybe better than anything we have now,” she says.

The motivation for this comes partly from quantum entanglement, the strange way in which two remote particles can be intertwined so that observations made on one can seemingly influence the results of observations on the other. It turns out that this can be described using information theory in a way that is highly general – the specifics of what is entangled don’t matter.

Marletto’s framework, derived with her colleague David Deutsch, is known as constructor theory. She is now trying to apply it to situations where our current best theories of physics are no good, for example at the intersection of quantum physics and gravity. Physicist Paul Davies at Arizona State University, meanwhile, has proposed that information could help us define what life is. He says the sophisticated manipulation of information is the thing that distinguishes living beings from inert matter.

One way or another, then, information seems likely to be our ultimate window on the universe. “The everyday appearance of things is a bit deceptive,” says Marletto. “You’ve got to put on some glasses to look at reality in a way that’s deeper.”

Cutting-edge science throws up all sorts of controversial, nebulous and mind-bending concepts. Here’s your guide to how to think about some of the fiddliest of them:

Topics: Physics

��ҹ��1000��

Physics